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以Zr-4和N18为研究对象,采用YAG激光焊接设备,通过抛切焊缝断面统计气孔数量,并观察焊缝中气孔位置和形貌,研究了非熔透性焊接过程中激光脉冲电流、脉冲宽度、离焦量等工艺参数以及脉冲激光调制对锆合金密集焊缝激光焊接气孔形成规律的影响。结果表明:在锆合金YAG激光非溶透性焊接过程中,气孔的形成主要源于焊接过程中匙孔的不稳定塌陷所形成的工艺型气孔,在熔池中气泡逸出熔池的速率低于熔池金属凝固速率的情况下会产生气孔。在满足焊缝熔深1.0 mm的情况下,随着激光脉冲电流、脉冲宽度的增加,气孔出现的几率逐步增加;随着离焦量的增加,气孔出现的几率逐渐减小;相比未分段编程模式,采用分段编程、电流缓降、降低焊接速度的方式,使焊缝气孔率明显降低,气孔尺寸有效控制在0.5 mm以下。
Taking Zr-4 and N18 as the research objects, the YAG laser welding equipment was used to measure the number of stomata in the welded section by observing the location and morphology of the stomata in the welded section. The effects of laser pulse current, Pulse width, the amount of defocus and other parameters and pulsed laser modulation dense zirconium alloy weld laser stomatal formation. The results show that during the process of non-penetrative YAG laser welding, the formation of pores mainly comes from the process-type pores formed by the unstable collapse of the keyhole in the welding process. The rate of bubble escape from the molten pool in the molten pool is low Stomatal will occur in the case of molten metal solidification rate. When the weld penetration depth is 1.0 mm, the probability of stomata increases with the increase of laser pulse current and pulse width. With the increase of defocus amount, the probability of stomata decreases gradually. Segment programming mode, the use of sub-programming, the current slowed down, reducing the welding speed of the way, so that weld porosity was significantly reduced pore size effectively controlled at 0.5 mm below.